1. Field of the Invention
The present invention relates to an imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor, a camera, a control method for the imaging device, and a computer program.
2. Description of the Related Art
A digital camera (hereinafter simply referred to as camera) mounted with a CMOS image sensor or the like in the past performs processing explained below in exposure control. First, the camera calculates illuminance (brightness) on a screen of a subject that should be imaged. As a method of calculating the illuminance, a method of integrating a luminance level included in an output signal of a pixel circuit over an entire pixel area is widely used.
Thereafter, the camera adjusts a gain, a stop value, and timing for an electronic shutter (also referred to as reset of the pixel circuit) according to this measured illuminance to thereby perform exposure control.
In an extremely dark place, the camera performs adjustment for fully opening a stop and executing the electronic shutter such that charge accumulating time of the pixel circuit is maximized, thereby increasing the gain. As the illuminance increases, the camera performs adjustment for decreasing the gain to 0 and adjusting the timing of the electronic shutter to reduce the charge accumulating time. In an extremely bright place, the camera performs processing for fixing the electronic shutter to close the stop.
As related arts, there are JP-A-2005-51352 and JP-A-2006-135708.